A (240,K) Reed-Solomon decoding algorithm for CMMB (China Mobile Multimedia Broadcasting) application is presented. A modified Euclid's algorithm (MEA) Reed-Solomon decoding method was implemented for the Key Equation Solver. And an improved Forney algorithm is also proposed. The modified algorithm was analyzed and compared with BM algorithm. The simulation result shows that the modified algorithm has such advantages as high efficiency and low complexity with good decoding performance. It meets the need of real- time communication.